With the release of 5.22 it states that "in Windows 8.1 and 10 [If you are using the "Windows SmartScreen Template from Beta 5.21.7, you will need to remove it after installing Sandboxie 5.22]". Does this mean that it has to be removed manually from Sandboxies configuration file "Template=SmartScreen" (for each instance of it)? Cheers

The Windows SmartScreen template was introduced with Sandboxie beta 5.21.7. If you manually added it to your sandboxes, you will have to remove it from each one of them before/after installing Sandboxie 5.22 (otherwise, you will receive an error message stating that the template doesn't exist).
You can follow the steps posted in the beta notes in order to remove it:

Thanks Barb,
That worked just fine and the error has gone now, have a great day .
BTW have been using Sandboxie for several years now since our family PC was fully malwared (with paid anti-virus installed) and have not had an issue since as it has saved us many times. I have installed it in all our PC's and have recommended it to several people over the years.

Hello I'm using sandbox from 7 years as you can see from my post, i've never got any problem from all beta and all official version, now i'm using firefox 56.0.2 (64 bit) on windows 7 64 bit ultimate, and i don't have sound on any video website like youtube for example, i've updated the flash (but now 90% of websites uses html5...), out of the sandboxie firefox works very well with the sound.

I'm using the release candidate of sandboxie with no extension on firefox 56.0.2 (64 bit) on windows 7 64 bit ultimate